U.S. patent number 7,269,154 [Application Number 10/721,283] was granted by the patent office on 2007-09-11 for wireless lan system for predicting movement destination of child station and wireless lan parent station therefor.
This patent grant is currently assigned to NEC Infrontia Corporation. Invention is credited to Hironori Hosoda, Yoshikazu Kobayashi.
United States Patent |
7,269,154 |
Hosoda , et al. |
September 11, 2007 |
Wireless LAN system for predicting movement destination of child
station and wireless LAN parent station therefor
Abstract
In the wireless LAN system including the child station and
parent stations, when each parent station detects handover of the
child station during QoS communication through a wireless
communication section, a table control section acquires the table
where MAC addresses of movement destination parent stations have
been registered and the band reserving request signal transmitting
section transmits the band reserving request frame to the parent
stations through a LAN communication section via Ethernet. The
table control section includes a registering means which registers
the acquired table, a deleting means which deletes the table and a
managing means which updates and manages the table.
Inventors: |
Hosoda; Hironori (Kanagawa,
JP), Kobayashi; Yoshikazu (Kanagawa, JP) |
Assignee: |
NEC Infrontia Corporation
(Kanagawa, JP)
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Family
ID: |
32376029 |
Appl.
No.: |
10/721,283 |
Filed: |
November 26, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040105417 A1 |
Jun 3, 2004 |
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Foreign Application Priority Data
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Nov 28, 2002 [JP] |
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2002-345849 |
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Current U.S.
Class: |
370/338;
455/432.1 |
Current CPC
Class: |
H04W
28/26 (20130101); H04W 36/32 (20130101) |
Current International
Class: |
H04Q
7/24 (20060101); H04Q 7/20 (20060101) |
Field of
Search: |
;370/338,331
;455/432 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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08-037680 |
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Feb 1996 |
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JP |
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09-046753 |
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Feb 1997 |
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JP |
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09-252480 |
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Sep 1997 |
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JP |
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2000-295649 |
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Oct 2000 |
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JP |
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2001-103531 |
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Apr 2001 |
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JP |
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2001-134541 |
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May 2001 |
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JP |
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2001-169325 |
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Jun 2001 |
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JP |
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2001-238245 |
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Aug 2001 |
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JP |
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Other References
Japanese Office Action dated Jan. 16, 2006 with English translation
of pertinent portions. cited by other.
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Primary Examiner: Feild; Joseph
Assistant Examiner: Doan; Kiet
Attorney, Agent or Firm: Whitham Curtis Christofferson &
Cook, PC
Claims
What is claimed is:
1. A wireless LAN system for predicting movement destination of a
child station, which includes the child station and a plurality of
parent stations, wherein each of said parent stations has a MAC
address and comprises: a wireless communication section for
conducting communication with the child station, the communication
including detecting a handover of said child station from said
parent station; a table control section acquiring a table having
the MAC address of each said parent stations that, relative to said
parent station, can be a movement destination parent station
registered, in response to said wireless communication section
detecting the handover of the child station; a band reserving
request signal transmitting section for generating a transmission
instruction for transmitting a band reserving request frame to all
of said plurality of movement parent stations having their
respective MAC address registered in said table movement
destination parent station; and a LAN communication section for
receiving the transmission instruction and transmitting the band
reserving request frame to the movement destination parent stations
via LAN, further comprising: a local area route information server
for providing a route information to each of said parent stations,
said route information representing a direction that a child
station cannot be moved in relation to said parent station, wherein
said parent station further comprises a route state determining
section for receiving and storing the route information and, based
on said stored route information, nullifying a transmission
instruction for transmitting a band reserving reguest to the parent
station positioned in the direction in which the child station can
not be moved.
2. The wireless LAN system according to claim 1, wherein each of
said parent stations further comprises: a transmitter for
transmitting a beacon signal identifying said parent station; a
signal strength measuring section for receiving and quantifying a
beacon signal of at least one adjacent parent station of the parent
stations, wherein said table control section receives information
of the qualified beacon signal and produces the table obtained by
selecting and registering only the parent stations which generates
a signal with a constant value or more, and when the child station
is moved, the band reserving request frame is transmitted to the
parent station which is predicted as the movement destination on
the basis of the movement destination parent station position
information which the table control section has.
3. The wireless LAN system for predicting movement destination of a
child according to claim 2, wherein said parent station further
comprises a movement direction determining section for comparing
MAC addresses of the parent stations existing in a movement source
and the movement destination of the child station with each other,
and for nullifying the transmission instruction of the reserving
request to the band reserving request signal transmitting section,
when the MAC addresses are the same.
4. The system according to claim 2, further comprising a local area
route information server for providing a route information to each
of said parent stations, said route information representing a
direction that a child station cannot be moved in relation to said
parent station, wherein said parent station further comprises a
route state determining section for receiving and storing the route
information and, based on said stored route information, nullifying
a transmission instruction for transmitting a band reserving
request to the parent station positioned in the direction in which
the child station can not be moved.
5. The system according to claim 2, wherein said table control
section counts the number of movement times of the child station
per movement destination to produce the table to represent the
probability of each of the parent stations being the movement
destination of the child station, and instructs to transmit the
band reserving request frame to the parent station with the highest
movement probability of the table.
6. The wireless LAN system for predicting movement destination of a
child according to claim 1, wherein said parent station further
comprises a movement direction determining section for comparing
MAC addresses of the parent stations existing in a movement source
and the movement destination of the child station with each other,
and for nullifying the transmission instruction of the reserving
request to the band reserving request signal transmitting section,
when the MAC addresses are the same.
7. The system according to claim 6, further comprising a local area
route information server for providing a route information to each
of said parent stations, said route information representing a
direction that a child station cannot be moved in relation to said
parent station, wherein said parent station further comprises a
route state determining section for receiving and storing the route
information and, based on said stored route information, nullifying
a transmission instruction for transmitting a band reserving
request to the parent station positioned in the direction in which
the child station can not be moved.
8. The system according to claim 6, wherein said table control
section counts the number of movement times of the child station
per movement destination to produce the table to represent the
probability of each of the parent stations being the movement
destination of the child station, and instructs to transmit the
band reserving request frame to the parent station with the highest
movement probability of the table.
9. The system according to claim 1, wherein said table control
section counts the number of movement times of the child station
per movement destination to produce the table to represent the
probability of each of the parent stations being the movement
destination of the child station, and instructs to transmit the
band reserving request frame to the parent station with the highest
movement probability of the table.
10. The wireless LAN system for predicting movement destination of
a child according to claim 1, wherein said table control section
counts the number of movement times of the child station for each
aspect of movement source per movement destination from association
setting information at a handover time to produce the table
obtained by calculating movement destination ratios of the child
station, and instructs to transmit the band reserving request frame
to the parent station with the highest movement probability of the
table.
11. A wireless LAN parent station for predicting movement
destination of a child station, comprising: a wireless
communication section for conducting communication with the child
station, the communication including detecting a handover of said
child station from said parent station; a table control section for
acquiring a table having the MAC address of each said parent
stations that, relative to said parent station, can be a movement
destination parent station registered, in response to said wireless
communication section detecting the handover of the child station;
a band reserving request signal transmitting section for generating
a transmission instruction for transmitting a band reserving
request frame to all of said plurality of movement parent stations
having their respective MAC address registered in said table
movement destination parent station; and a LAN communication
section for receiving the transmission instruction and transmitting
the band reserving request frame to the movement destination parent
stations via LAN, further comprising: a local area route
information server for providing a route information to each of
said parent stations, said route information representing a
direction that a child station cannot be moved in relation to said
parent station, wherein said parent station further comprises a
route state determining section for receiving and storing the route
information and, based on said stored route information, nullifying
a transmission instruction for transmitting a band reserving
request to the parent station positioned in the direction in which
the child station can not be moved.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flow prediction QoS (Quality of
Service) control, and in particular to a wireless LAN system for
predicting movement destination of a child station for reserving a
band required for QoS control in advance.
2. Description of the Related Art
In the wireless LAN system, conventionally, when the child station
moves to conduct handover, a parent station which is a roaming
destination must reserve the band required for QoS communication.
Therefore, it has been difficult to conduct real time QoS control
at a time of handover.
Further, in Japanese Patent Publication No. 2001-103531 A, there
has been disclosed a wireless LAN base station selecting system
constituted so as to notify a mobile terminal moving between
wireless LAN base stations of base station information whose
contents are ranked in the order of higher probability of movement
of the terminal utilizing information obtained statistically from
movement information of the mobile terminal to conduct switching to
another base station efficiently.
However, conventionally, as movement of the child station, it takes
much time for the parent station which is a roaming destination to
reserve the band required for QoS communication, which results in
deterioration of a real time property of communication.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide the
wireless LAN system for predicting movement destination of the
child station where the parent station which has detected handover
of the child station causes another parent station which is
predicted as the next roaming destination to reserve the band
required for controlling QoS communication so that communication
whose real time property is not negatively affected can be achieved
even while the child station is moving in a broad range.
In order to solve the above-described problem, according to the
present invention, there is provided the wireless LAN system for
predicting movement destination of a child station, which includes
the child station and parent stations, wherein each parent station
comprises: a wireless communication section which conducts
communication with the child station, a table control section which
acquires a table in which MAC address of each movement destination
parent station has been registered when handover of the child
station put under QoS communication is detected through the
wireless communication section; the band reserving request signal
transmitting section which transmits a transmission instruction of
the band reserving request frame to the movement destination parent
station; and a LAN communication section which receives the
transmission instruction and transmits the band reserving request
frame to the movement destination parent station via LAN.
With the above constitution, it is made possible to cause the
parent station which is predicted to be the next movement
destination to reserve a band prior to handover of the child
station.
As described above, according to the present invention, since the
parent station which is predicted to be the next movement
destination to reserve a band prior to handover of the child
station, a loss time required for reserving the band required for
the QoS control can be avoided in advance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a basic configuration diagram of the parent station
according to the present invention;
FIG. 2 is an explanatory diagram of the table in which a MAC
address of a movement destination parent station has been
registered;
FIG. 3 is a configuration diagram of the wireless LAN system in a
first embodiment;
FIG. 4 is a diagram showing a communication enabling area of
adjacent parent stations in the first embodiment;
FIG. 5 is a configuration diagram of the parent station in the
first embodiment;
FIG. 6 is a diagram showing information about movement destination
parent station addresses stored in the table control section of the
parent station in the first embodiment;
FIG. 7 is a configuration diagram of the parent station in a second
embodiment;
FIG. 8 is a configuration diagram of the wireless LAN system in a
third embodiment;
FIG. 9 is a configuration diagram of the parent station in the
third embodiment;
FIG. 10 is a diagram showing communication enabling area of
adjacent parent stations in a fourth embodiment; and
FIG. 11 is a diagram showing information about predicted movement
destination of the child station stored in the table control
section of the parent station in the fourth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Next, embodiments of the present invention will be explained with
reference to the drawings.
FIG. 1 shows one example of a basic configuration of the parent
station according to the present invention. When the parent station
detects handover of the child station put under QoS communication
via wireless communication section 10, table control section 20
acquires the table in which MAC addresses of movement destination
parent stations have been registered, such as shown in FIG. 2, and
the band reserving request signal transmitting section 30 transmits
the band reserving request frame to the parent stations through LAN
communication section 40 via Ethernet (registered trademark.RTM. of
Xerox Co., Ltd). The table control section 20 includes registering
means 21 which registers an acquired table, deleting means 22 which
deletes the table and managing means 23 which updates and manages
the registered table.
Since the parent station which is predicted to be the movement
destination is caused to reserve the band prior to handover of the
child station, a time loss required for such a processing can be
avoided in advance.
FIGS. 3 to 5 show a configuration of the wireless LAN system, and a
communication enabling area obtained by the configuration and a
configuration of the parent station.
In a system configuration shown in FIG. 3, it is assumed that the
child station movement positions P1 to P5 are positioned on courses
just below parent stations 1 to 5, and the child station can freely
move to these positions. Further, it is assumed that, since a
communication enabling range of each parent station is disposed so
as to overlap with respective communication enabling areas of
adjacent parent stations, such as shown in FIG. 4, each parent
station can receive beacon signals from the adjacent parent
stations.
FIG. 5 shows a configuration of the parent station of this
embodiment. Beacon signal strength measuring section 50 quantifies
the strength of an interception signal from each adjacent parent
station with RSSI (Receive Signal strength Indication). The table
control section inputted with information about the strength
selects only the parent station which transmits a signal with a
predetermined value or more and registers the same so that the
table can be processed as movement destination position parent
station information to which the child station may move.
For this reason, in the wireless LAN system according to this
embodiment, when the child station has been moved from the movement
position P1 to the movement position P2, the parent station 2 can
transmit the band reserving request frame to each of the parent
stations 1, 3, 4 and 5, which is predicted as one movement
destination, on the basis of the movement destination position
parent station information (refer to FIG. 6).
Incidentally, the wireless LAN system of this embodiment has such a
feature that, since a movement prediction table is produced on the
basis of the strengths of interception signals, it is unnecessary
to input information about the parent station positions into the
table control section manually, and the contents of the table can
be updated automatically even when the arrangement constitution of
the parent station is modified.
FIG. 7 is shows a configuration of the parent station in a second
embodiment of the present invention. Incidentally, a configuration
and a communication enabling area of the wireless LAN system in
this embodiment are the same as those in the first embodiment.
The parent station of this embodiment is constituted to conduct
perform functions such that the information about movement
destination parent stations is registered in the table control
section in the same manner as the first embodiment. However, the
parent station of this embodiment has a function that, when the
band reserving request frame is transmitted to each parent station
registered in the table, a movement direction determination section
60 compares MAC addresses of the parent stations existing in the
movement source and the movement destination with each other and it
can nullify a transmission request of the reserving request to the
band reserving request signal transmitting section 30 when the MAC
addresses are the same.
For this reason, in the wireless LAN system of this embodiment,
when the child station is moved from the movement position P1 to
the movement position P2, the movement destination predicted from
the movement destination parent station position table of the
parent station 2 will be the one of the parent stations 1, 3, 4 and
5 (refer to FIG. 6), however, a band reserving request frame is
eventually transmitted to the parent stations 3, 4 and 5.
The wireless LAN system of this embodiment has an advantage that an
unnecessary band use can be avoided in a place where a movement
aspect in which a person carrying the child station returns is
hardly considered, such as a corridor.
FIGS. 8 and 9 show a configuration of the wireless LAN system and a
configuration of the parent station in a third embodiment of the
present invention. Incidentally, it is assumed that a communication
enabling area of this embodiment is the same as that in the first
embodiment.
It is assumed that, since the system configuration of the third
embodiment is constituted such that a course with a T shape is used
instead of the course (FIG. 3) with a cross shape, the child
station can not move directly to the child station movement
position 3. A local area route information server 6 for providing
route information in an institution to each parent station exists
on the Ethernet.
Information from the route information server 6 is stored in route
state determining section 70 shown in FIG. 9 where the information
is used as material for determining a direction in which the child
station can not move directly. For this reason, in the wireless LAN
system of this embodiment, when the child station is moved from the
movement position P1 to the movement position P2, the movement
destination which is predicted from the movement destination parent
station position table in the parent station 2 includes the parent
stations 1, 3, 4 and 5 (refer to FIG. 6). However, since the band
reserving request to the parent station 1 is rejected by the
movement direction determining section 60 and the band reserving
request to the parent station 3 is rejected by the route state
determining section 70, the band reserving request frame is finally
transmitted to only the parent stations 4 and 5.
Since the wireless LAN system of this embodiment does not transmit
the band reserving request to the parent station to which the child
station can not actually move on the basis of the route information
provided from the server, more efficient band use can be expected
as compared with the foregoing embodiments.
A fourth embodiment of the present invention has the same
configuration as the first embodiment regarding the wireless LAN
system and the parent station (FIGS. 3 and 5). Incidentally, as
shown in FIG. 10, it is assumed that, since each parent station
does not cover communication areas of parent stations adjacent
thereto, the movement destination parent station position
information can not be acquired from interception signals.
A table control section of the parent station which has detected
handover of the child station during QoS communication counts the
number of movement times for each aspect of a movement source per
movement destination from association setting information at a time
of handover to calculate a movement destination ratio.
As a result, the table control section of the parent station 2 in
the wireless LAN system of this embodiment eventually has the
movement destination predicting information of the child station
such as shown in FIG. 11. For example, when the child station is
moved from the movement position P1 to the movement position P2,
the band reserving request frame is eventually transmitted to the
parent station 5 with the highest movement probability selected
from the table.
In the wireless LAN system of this embodiment, the frequency or the
number of movement times must be sampled to some extent in order to
improve accuracy of the movement prediction, however, realization
can be made possible without interception of adjacent station
signals or preparing a map server like the above embodiments.
* * * * *